Synchronizing device



Aug. 14, 1928.

F. H. WINTER SYNCHRONIZING DEVICE Original Filed Nov. 26, 1926 Fig.1.

- lnvefitbr; Zed H.Win ter; His Attorney.

nection is completed.

Patented Aug. 14, 1928.

UNITED STATES PATENT OFFICE.

FRED H. WINTER, F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK;

SYNGHRONIZING DEVICE.

Application filed November 26, 1926, Serial No. 150,869. Renewed April21, 1928.

My invention relates to improvements in synchronizing devices, and hasfor an object to provide an improved synchronizing device forautomatically controlling the operation of connecting two alternatingcurrent circuits whereby to provide for the time of the closingoperation of the connecting means so that the connection can occur onlywhen the electromotive'forces of the circuits are substantially alike inphase and frequency.

When two energized alternating current circuits or systems are to beconnected, it is desirable that their electromotive forces be alike inphase and fre uency, when the conhe connecting opera- 7 tion should,therefore, be started sufliciently prior to the in-phase andin-frequency condition to allow for the time of operation of theswitching means by which the circuits are to be connected; While thisswitching operation may be started over a considerable range in thephase difference when the difi'erence between the frequencies is lessthan a )redetermined value, as disclosed in United iatatesLetters Patent1,563,120, issued to Oliver 0. Traver November 24, 1925, and assigned tothe same assignee as this invention, I propose to use synchronizingapparatus comprising a light responsive means, in order to increase thesensitivity of. the synchronizing apparatus which, in order to reducethe chances of connecting the circuits when they are not in phase and infrequency, may be arranged further to limit the conditions under whichthe switching operation can be started to only a predetermined phasedifi'erence when the difference between the frequencies is less than apredetermined value.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying drawing, and itsscope will bepointed out in the appended claims.

In the accompanying drawing, Fig. 1 illustrates diagrammatically anembodiment of my invention, and Fig. 2 is a detail of a part of myinvention,

For purposes of illustration, I'have shown in Fig. 1 an embodiment of myinvention as applied to a three-phase alternating current electricsystem comprising two alternating current circuits 1 and 2 which may beconnected by any suitable circuit controlling or switching means 3. Thisswitching means, as shown, is of the latched closed type, and comprisesa closing coil 4 whose circuit is arranged to be energized from asuitable source 5 through the contacts 6 of a control relay 7'which, asshown, is of the instantaneous closing time delay opening type. Thiscontrol relay 7 is arranged to be energized from a suitable source suchas a control bus 20 and to be controlled through the contacts 8 of asubstantially instantaneous relay 9 and the contacts 10 of a time limitrelay 11 only when both of the relays are simultaneously in circuitcontrolling position.

In order to control the relays 8 and 10, and through them the switch 3,so that circuit closing operation thereof is started sufficiently priorto the in-phase and in-frequency condition of the electromotive forcesof the circuits land 2 toallow for the time of the closin operation ofthe switch, I provide mova le means such as a disk 12 which iscontrolled in accordance with the difference between the frequencies ofthe electromotive forces. For this there may be used any suitable means,such as a dynamo-electric machine comprising a shaft 13 to which thedisk is secured, a rotor winding 14 connected to be energized from thecircuit 2 through any suitable means such as a potential transformer 15,and a stator winding 16 connected to be energized from the circuit 1through any suitable means such as a potential transformer 17. The tworotating three-phase alternating magnetic fields produced by thewindings 14 and 16, as is well known, cause movement of the rotor and,therefore, the disk 12 at an angular velocity dependent on thedifference between the frequencies of the electromotive forces and-in adirection depending on which of the circuits has the greater frequency;

In order to employ the movement of the disk 12 without impairing itssensitivity by reason of having tov accelerate contacts, store energy insprings and the like, I provide light responsive means herein shown ascomprising'photoelectric cells 18 and- 19 which are'arranged to becontrolled in acpurpose cordance with the movement of the disk, and ycontrol theenergization of the relays 9 and 11 whose windings areconnected to a suitable source such as the control bus 20.

For controlling these photoelectric cells, I provide a suitable source-of light such as an incandescent lamp 21 which is mounted on theopposite side of the disk 12 from the cells. When the disk 12 is inpredetermined positions, light passing portions. such as apertures ortransparent sections 22, 23, 24 and 25 permit light from the lamp 21 toreach mirrors 26, 27, 28 and 29, respectively, the lamp being suitablyshielded so that the light therefrom is not promiscuously distributed.Light from the lamp 21 passing through either the apertures 22 or 24strikes the mirror 26 or 28 and is reflected therefrom to the lightsensitive surface of the photoelectric cell 19. When the cell is thusenergized, suflicient current is passed through the winding of the timelimit relay 11 to start'the circuit controlling operation thereof. Ifthe light from either of the apertures 22, 24 is reflected on the cell19 for a time corresponding to the setting of the relay 11, it willclose its contacts 10. The time durin which the cell 19 is energized is,of course, dependent on the angular velocity of the disk 12 and theangular extent or length of the apertures 22, 24. Since the angularvelocity of the disk 12 is dependent on the frequency difference, theapertures 22,

24 will have a length correspondmg to somepredetermined frequencydifference which it is undesirable to exceed when the switch closingoperation is to be started. The time and, therefore, the predeterminedvalue of the frequenc' difference may be varied by changing eit er theangular extent of the apertures 22, 24 or the time setting of the relay11. V I

In order to make it possible to start the closing operation of theswitch 3, whether the frequency of one of the circuits is greater orless than the frequency of the other, the two sets of apertures 22, 23and 24, 25 and their res ectively associated mirrors are provided.Sthe'rwise, only one setmay be emplozed. Thus, if the frequencydifference is suc that rotation of the disk 12 is in the directionindicated by the arrow 30, the aperture 22 will function to control therelay 11. If the rotation is in the opposite direction, the aperture 24functions. Where both apertures 22 and 24 are employed, it is preferablein order to prevent any possibility of completing the circuitcontrolling o eration of the time limit relay 11 when the sk 12 isrotating at a velocity such. as in effect to ,combinethe lengths of thetwoapertures 22 and 24, to arrange them on radii of different lengths.This makes it impossible for the timing operation of both of theapertures 22 and 24 to become cumulative. Adjacent the trailing ends,the lower ends as seen in Fig.

1, of the apertures 22 and 24 are the cooperating apertures 23 and 25.These are relatively short apertures through which light. from the lamp21 passes to the mirrors 2? and 29, respectively. From these mirrors thelight is reflected to the light sensitive surface of the cell 18 tocontrol the energization of the instantaneous relay 9. The trailing endsof the apertures 22,24 and the apertures 23, 25 are angularly so locatedon the disk 12 as to permit the contacts 8 and 10 to be in circuitclosing positions at a predetermined phase difference between theelectromotive forces of the circuits 1 and 2.

For varying the phase difference at which the switch closing operationcan be started, the angular positions of theapertures in the disk 12 maybe varied in any suitable manner. One way of doing this is shown in Fig.2, wherein as shown by the dotted lines the angular extent of theapertures in the disk 12 is considerably increased and. wherein movablemembers such as sectors 31 and 32 are provided with apertures 22', 23',24 and 25, corresponding, for example, in angular extent to those in thedisk 12 of Fig. 1. These sectors, as shown, are arranged for movementabout the axis of rotation of the disk 12, and permit a definite angularextent of opening in the apertures in the disk, so that the angulardisposition of the apertures can be varied as desired to change thephase relation at which operation of the switch 3 is started.

In explaining the operation of the illustrated embodiment of minvention, it will be assumed that the diflerence between thefrequencies of the electromotive forces of the circuits 1 and 2 is suchas to cause rotation of the disk 12 in the direction indicated by thearrow 30. .Thcn when the upper or leading end of the aperture 22 hasmoved suflicientl to permit light from the lamp 21 to reach t c mirror26, the photoelectric cell 19 is energized and starts the'time limitrelay 11 operating. If the frequencydifference is below thepredetermined value for which the timing of the relay is set, then thecontacts 10 Will be closed by the time the aperture 23 has moved to aposition which permits light from the lamp 21 to reach the mirror 27 andthus to effect the energization of the photoelectric cell 18. Theinstantaneous relay 9 is thus energized to close its contacts 8 at apredetermined phase difference between the electromotive. forces of thecircuits 1 and 2. Whenboth of the contacts 8 and 10 are closed, thecontrol relay 6 is energized. This relay completes the circuit of theclosin coil 4 of the switch 3 sufiiciently prior to t e inhase andinfrequency condition to allow or the time of the closing operation ofthe switch. Although in Fig. 1, the disk 12 is shown in theinstantaneous position corresponding to the phase relation at which theinstantaneous relay 9 is energized to start the closing operation, theswitch 3 is shown in the closed position since the time dimension, thatis, the time to close the switch after the control relay is energized,cannot be illustrated simply in a drawing.

Considering again rotation of the disk 12 in the direction indicated bythe arrow 30, it is obvious that, as the aperture 24 is moved into anangular position such that light can strike the mirror 27, the cell 18may effect operation of the instantaneous relay 9. This, however, cannoteffect incorrect closing of the switch 3 since, although the aperture 25may be moved into an angular position such that light can strike themirror 26, the cell 19 will not be energized for a time sufficient tocausecircuit closing operation of the time limit relay 11. In otherwords, although one of the relays 9, 11 may be actuated to close itscontacts, the other will not be in circuit closing position at the sameinstant except when predetermined conditions, such that it is safe tostart the switch closing operation, prevail.

It will be understood that, if desirable, I may provide an additionalcontrol operative in response to the relative values of theelectromotive forces of the circuits 1 and 2. Examples of such means areWell known in the art, one suitable means being disclosed in LettersPatent 1,563,120 heretofore referred to. Such additional control, whichmay comprise further contacts in the control circuit, is desirable wherethe circuits are to be connected only when their electromotive forcesare nearly equal in value.

lVhile I have shown and described only one embodiment of my invention, Ido not desire to be limited to the exact arrangement shown anddescribed, but seek to cover in the appended claims all thosemodifications that fall within the true spirit and scope o my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, a plurality of alternating current circuits, meansfor connecting said circuits and means comprising a light responsivedevice for starting the closing operation of the connecting means ata-predetermined phase difference of the electromotive forces of thecircuits when the difference between the frequencies of theelectromotive forces is less than a predetermined value for apredetermined time.

2. In combination, a plurality of alternating current circuits, meansfor connecting said circuits, and means controlled in accordance withthe difference between the frequencies of the electromotive forces ofthe circuits and comprising a light responsive device for starting theclosing operation of the connecting means at a predetermined phasedifference of the electromotive forces when said frequency difference isless than a predetermined value for a predetermined time.

3. In combination, a plurality of alternating current circuits, meansfor connecting said circuits and, means comprising a light responsivedevice for starting the closing operation of the connecting means whenthe difference between the frequencies of the electromotive forces ofthe circuits is less than a predetermined value for a predeterminedtime.

4. In combination, a plurality of alternating current circuits, meansfor connecting said circuits, and means controlled in accordance withthe difference between the frequencies of the electromotive forces ofthe circuits and comprising a light responsive device for starting theclosing operation of the connecting means at a predetermined phasedifference of the electromotive'forces when the frequency difference isless than a predetermined value.

5. In combination, a plurality ofalternating current circuits, means forconnecting said circuits, means comprising a light responsivedevicearranged to be controlled in accordance with the differencebetween the frequencies of the electromotive forces of the circuits forcontrolling the closing operation of the connecting means.

6. In combination, a plurality of alternating current circuits, meansfor connecting the circuits, and means for controlling the closingoperation of the connecting means comprising a movable member arrangedto be actuated at a velocity dependent on the difference between thefrequencies of the electromotive forces of the circuits and lightresponsive means comprising a photoelectric cell arranged to-becontrolled by said memher.

7. A synchronizing device comprising a rotatable member adapted to berotated at a velocity dependent on the difference between thefrequencies of two alternating electromotive forces and light responsivemeans ar ranged to be controlled in accordance with the angular velocityand position of the member.

8. A synchronizing device comprising a substantially instantaneousrelay, a time limit relay and controlling means therefor comprising amember adapted to be rotated at a-velocity dependent on the differencebetween ;the frequencies of two alternating electromotive forces andlight responsive means arranged to be controlled by said member toeffect the circuit controlling op- .eration of said instantaneous andtime limit relays in accordance with the angular posi tion and velocityrespectively of said member.

9. In combination, a plurality of alternating current circuits, meansfor connecting said circuits, means for controlling the clos ing of saidconnecting means comprising a time limit relay and means for controllingthe circuit closing operation of said relay comprising a movable memberarranged to be actuated in accordance with the difference between thefrequencies of the electromotive forces of said circuits and lightresponsive means comprising a photoelectric cell controlled inaccordance with the velocity of said member for effecting the circuitclosing operation of said relay when the velocity of the member is lessthan a predetermined value. v

10. In combination, a plurality of alternating current circuits, meansfor connecting said circuits, means for starting the closing operationof said connecting means comprising a substantially instantaneous relayand a time limit relay, means for controlling the circuit closingoperation of said relays comprising a movable member arranged to beactuated in accordance with the difference between the frequencies ofthe electromotive forces of said circuits, and light responsive meanscontrolled in accordance with the velocity of said member for effectingthe circuit closing operation of the time limit relay .when the velocityof the member is less than a predetermined value and the circuit closingoperation of the instantaneous relay when the member is in apredetermined position.

11. A synchronizing device comprising a member adapted to be rotated ata velocity dependent on the difference between the frequencies of twoelectromotive forces, a source of light, a plurality of light sensitivemeans, and means associated with said member for permitting light fromsaid source to sensitize one of said means for a time dependent on theangular velocity of the member and another of said light sensitive meanssubstantially instantaneously when the disk is in a predeterminedposition.

12. A synchronizing device comprising a member adapted to be rotated ata velocity dependent on the difference between the frequencies of twoelectromotive forces, 'a source of light, light sensitive means, andmeans associated with said member for permitting light from said sourceto sensitize said means when the velocity of the member is less than apredetermined value during a predetermined movement and the member is ina predetermined position.

18. A synchronizing device comprising a member adapted to be rotated ata velocity dependent on the difference between the frequencies of twoelectromotive forces and having light passing portions of relativelysmall and large extent, a source of light on one side of. said memberand light sensitive means on the other side of said member arranged toreceive light from'said source when the smaller portion is in apredetermined position and while the other portion is moving through apredetermined angle.

let. A synchronizing device comprising a member adapted to be rotated ata velocity dependent on the difference between the frequencies of twoelectromotive forces and having light passing portions of relativelysmall and large extent, a source of light on one side of said member,light reflecting means on the other side of said member arranged toreceive light from said source when the smaller portion is in apredetermined position and while the other portion is moving through apredetermined angle, light sensitive means arranged to receive lightreflected from said light reflecting means, and means comprising acontrol circuit arranged to be controlled by said light sensitive meansand to lie-completed when the angular velocity of the member is lessthan a predetermined value during a predetermined movement of the memberand the member is in a predetermined position.

In witness whereof, I have hereunto set my hand this 24th day ofNovember, 1926.

FRED H. WINTER.

